Canada, Israel and Sweden announced yesterday they will accept more Indochinese refugees. At the same time, however, refugee-burdened Malaysia was preparing to ship thousands of Vietnamese back to sea.

Malaysia's navy intercepted two large Vietnamese refugee boats trying to land and escorted them back into international waters.

The Malaysian patrol boats apparently reprovisioned the 100-foot boats before escorting them out to the South China Sea. There was no indication where the boats, which carried an estimated 2,000 refugees, could go.

In Hong Kong, officials reported that about 60 Vietnamese "boat people" were stranded on an oil rig in the South China Sea. The officials said the rig's crew had radioed a request for any passing ship to take the refugees off.

Many nations, including Vietnam, have endorsed the idea of convening some type of an international conference on the refugee issue. But U.N. High Commissioner for Refugees Poul Hartling cautioned against hurriedly convening a conference that could deteriorate into a "counterproductive" exchange of accusations.

Several nations announced new help for the refugees:

The Canadian government said it would expand its worldwide refugee quota by 1,000 to make room for more Indochinese.

Prime Minister Menachem Begin's office announced that Israel, which over the past two years has taken 168 boat people, would accept 200 more Vietnamese refugees. Begin earlier this week called on all nations to take in Indochinese refugees in proportion to their own populations.

The Swedish government said it would take in 1,500 Indochinese refugees beginning this fall. Sweden accepted 262 boat people last year.

The Taiwan government announced it would donate almost $300,000 and 10,000 tons of rice to help care for refugees now in Malaysia, Thailand and Hong Kong. Taiwan said it has taken in almost 12,000 refugees since 1975.

The United States reports it has taken in more than 200,000 Indochinese refugees since 1975 and is accepting more at a rate of 7,000 a month. U.S. officials said in Washington that the administration is considering raising that quota.

Meanwhile, Malaysian officials said the governments of Malaysia, Thailand, Indonesia, the Philippines and Singapore would adopt a "joint diplomatic stand" on the refugee problem when their representatives meet next Thursday in Bali, Indonesia.

In other developments, Vietnamese troops, tanks and artillery moved into two areas along the Thai-Cambodian frontier, raising fears of a strike across the border to hit hiding Khmer Rouge guerrillas, military sources in Bangkok said.

Thai Prime Minister Kriangsak Chamanan warned, "We are ready to pull the triggers of our guns if our sovereignty is violated."

Thai military spokesmen said they could not guess the intentions of the Vietnamese, but they reported a continuing buildup and increased patrols along the Cambodian side of the border. CAPTION: Picture, Vietnamese refugees watch Malaysians stock supplies for boats in which they will be sent back to sea. AP