More than 20 extra Australian Federal Police officers are expected to fly to Christmas Island to quell possible disturbances as authorities intercepted the first asylum-seekers to fall victim to the Rudd government’s suspension of new refugee claims.

Four boats carrying more than 230 people have been intercepted since Immigration Minister Chris Evans announced on Friday a six-month suspension of all new Afghan asylum claims, and a three-month suspension for Sri Lankan claims.

A boat carrying 25 passengers, understood to be predominantly Afghans, was stopped by Customs and Border Protection personnel yesterday near Browse Island, off Western Australia’s north coast. Later yesterday, another vessel, this time carrying 30 passengers and four crew, was intercepted by the navy in the Ashmore Islands, also off WA’s north coast.

As the interceptions were occurring, Foreign Minister Stephen Smith conceded the policy changes were unlikely to have any immediate impact. “We’re not asserting or suggesting this will stop the flow of boats in the short term,” he said.

Tony Abbott continued the Coalition attack on the asylum claims freeze, labelling it a stunt to get the government through the federal election.

Yesterday’s arrival may be the first boat to be affected by the suspension, which was designed to send a signal to asylum-seekers and people-smugglers that Australia is not a soft touch. It was not known if the passengers aboard the boat had been told of the policy changes, which will ensure a minimum six-month stay in detention should they proceed with refugee claims.

But in a clear sign authorities are concerned the policy shift could trigger violence in the detention centre, the AFP yesterday moved to boost its presence on Christmas Island. The Australian understands an extra 24 officers were due to fly in yesterday, but were delayed by poor weather. They will join the 17 officers understood to have flown in on Friday, plus a smaller contingent that arrived on Saturday.

On Friday, the officers held a meeting with senior immigration officials before unpacking riot gear, including shields. A freight plane that arrived on Christmas Island on Saturday is understood to have included tear gas, rifles and ammunition.

The insignia worn by some of the officers suggests they are members of the elite Operational Response Group, the AFP’s offshore tactical unit.

However, there was no trouble at any of the island’s detention centres yesterday. Afghans and Sri Lankans were told through interpreters on Friday that the claims decision would not affect their cases, although many are worried that their chances of being granted asylum are less hopeful if the government believes conditions are improving in their home countries.

Refugee Immigration and Legal Centre co-ordinator David Manne, who is on Christmas Island visiting asylum-seeker clients, said the announcement had created considerable confusion and anxiety among detainees. “For those not caught by the freeze, they are still finding it difficult to believe there won’t be a negative impact on their cases as well,” he said. “Some asylum-seekers sense there’s a potentially serous misunderstanding and trivialisation of the grave dangers they believe they would face if they returned to Afghanistan.”

The Immigration Department said yesterday there were 2162 detainees on Christmas Island, well above the official operating capacity of 2040. To ease the pressure, the department is trying to install new accommodation that would supply an extra 400 beds on the island, and a charter flight with a seating capacity of 177 is expected to leave today.

But with 202 intercepted asylum-seekers and crew en route to the island, combined with the bottleneck on new asylum claims looming due to the freeze, a spill to the mainland is considered virtually inevitable.

Mr Smith admitted yesterday there was little prospect the suspension of claims would have any immediate impact on the number of boats arriving, which has been steadily increasing. “But it does send a message to the people-smugglers, and to their potential prey, that if you come to Australia from Sri Lanka or from Afghanistan, there’ll be a three-month or six-month pause, and you will not be guaranteed a visa.”

Mr Smith denied the government had effectively consigned new asylum-seekers to indefinite detention, a fate Senator Evans described in February as worse than prison. “Once processing resumes, none of the rights that are currently accorded or afforded to them will be taken away from them,” Mr Smith said.

The Opposition Leader said of the freeze: “They’re trying to say you won’t be processed for three months or for six months, but let’s face it, people were waiting months on Christmas Island anyway.” But Mr Abbott declined to say if a Coalition government would maintain the freeze should it win the federal election, which is expected in coming months.

A spokesman for the Indonesian Foreign Ministry, Teuku Faizasyah, offered tacit support for the measures, but said they were a matter for Australia. “In the broader perspective, any measure that prevents people from travelling illegally will suit any country in the region,” he said.