"Mr Tony Blair is the main ally of Hitler," Chavez, who has recently taken to comparing Bush to Adolf Hitler, the Nazi leader, said on Wednesday.
Chavez criticised Blair for urging Venezuela to abide by the rules of the international community and saying he would like to see true democracy in communist-led Cuba, Venezuela's closest ally in Latin America.
Blair "is being nothing but a pawn of imperialism trying now to attack us from Europe", Chavez told supporters during a speech in western Venezuela.
The comments were Chavez's harshest yet against Blair, whom he has criticised in the past over the war in Iraq.
Chavez was responding to comments made by Blair earlier on Wednesday during a weekly question-and-answer session in the House of Commons.
"It is rather important that the government of Venezuela realise that if they want to be respected members of the international community, they should abide by the rules of the international community," Blair said according to an official transcript.
The Venezuelan leader's remarks on Wednesday came amidst a diplomatic row with the US, which has brought relations between Caracas and Washington to their lowest point in years.