Mugabe on Sunday suggested US and British firms could be targeted. "They should not continue to harass us," the 89-year-old veteran leader told mourners at a funeral.
"We have British and American companies here and we are treating them well. There will come a time when we will lose our patience."
The United States and European Union imposed sanctions including travel bans and asset freezes on Mugabe and members of his inner circle and several companies following 2002 elections which western observers said were rigged.
"They have companies here and we have not imposed controls or sanctions against them but time will come when we will say tit-for-tat. You hit me, I hit you. You impose this on me, I impose this on you," Mugabe said.
"Our attitude is not going to continue as it was in the past – passive. We have had enough and enough is enough."
Mugabe won an extension to his 33-year rule in general elections last month, which was slammed as "a farce" by his rival and prompted serious concerns from western nations.
Local observers said the elections were fraught with irregularities but observers from the African Union and the regional Southern African Development Community bloc were less critical.
Controversial equity drive
Mugabe was sworn-in last week after the Constitutional Court declared the elections "free, fair and credible".
He has vowed to forge ahead with his controversial equity drive to force foreign companies to cede majority shares to local investors.
So far mining companies including Zimplats, a subsidiary of the South African-based Impala Platinum and Anglo American Corporation's Unki mines have been forced to sell their majority stake to locals.
Companies in the retail sector are set to follow.
The EU earlier this year retained an asset freeze and travel ban on Mugabe but eased most of its decade-old restrictions on Zimbabwe.
The majority of those on the US sanctions list still remain, including a travel ban and asset freeze on individuals and entities with links to Mugabe.
Mugabe was addressing mourners at the burial of Mike Karakadzai, a retired air commodore and hero of the 1970s liberation war, who died aged 56 on Tuesday.