The European Common Market accused South Africa yesterday of introducing measures in Namibia that are incompatible with the U.N.-approved independence plan for the territory.

Britain's U.N. representative, Sir Anthony Parsons, speaking on behalf of the Common Market, told the U.N. General Assembly: "We reject any attempt to impose an internal settlement on Namibia."

He said South Africa and its administrator general in Namibia have introduced conscription, extended the powers of the territory's "so-called council of ministers" and brought in second-tier elections for the various ethnic groups.

"In the view of the 10 Common Market members these actions are divisive. They exacerbate tensions inside the territory. They are not consonant with an internationally acceptable solution," he added.

Parsons was addressing the General Assembly as it resumed its emergency special session on the future of the former German colony, which South Africa continues to administer in defiance of U.N. resolutions.

Parsons said it was of the utmost importance that South Africa abide by its declared willingness to let Namibia attain independence in accordance with the U.N. plan.

An opportunity to set the plan in motion at a U.N. conference in Geneva last January was lost "through South Africa's prevarication, for which we see no justification," he said.