WASHINGTON (AP) _ A member of the House Ways and Means Committee is a business partner with a lobbyist who often works on issues before the tax-writing panel, according to disclosure forms and an aide to the congressman.

Rep. Beryl Anthony, D-Ark., and R. Duffy Wall each own one-third of Porterco Inc., a Magnolia, Ark., company whose primary product is soft-sided portable ice chests. The business relationship was first reported Friday in the Wall Street Journal.

Anthony reported his stake in the company in his annual financial disclosure form, which shows that he is a director and part owner of the 60- employee firm.

Wall and Anthony paid $190,000 each for their shares in the company in 1988. An aide to Anthony, Karen Hancox, said Friday that company founder Calvin Porter began early this year a process of buying back Wall's share of the company.

Hancox said any implication that the business relationship was improper was erroneous. ''There isn't anything that is illegal or a violation of House ethics rules,'' she said.

She added that the friendship between the two men dates to just before Anthony was elected to Congress in 1978, when they met through mutual friends.

''Duffy Wall has never lobbied Beryl personally'' on any issue before the Ways and Means Committee, she added, although Wall routinely works the panel on behalf of clients like the Pharmaceutical Manufacturers Association and the Securities Industry Association.

Wall has lobbied on behalf of a capital gains tax cut and a tax break for the drug industry, both of which Anthony favored all along, Hancox said.

''He has never changed a stand on legislation because of Mr. Wall,'' Hancox said.

While Anthony was chairman of the Democratic Congressional Campaign Committee, the organization bought some $6,500 worth of merchandise from Porterco. Anthony told the Journal he did not place the orders, but saw nothing wrong with them as long as no special consideration was given.