Parti Amanah Negara (Amanah) president Mohamad Sabu's accusation that Malaysia was 'bought' by Saudi Arabia to join a big group in the Middle East was baseless and mere political polemic.

UMNO vice-president Datuk Seri Hishammuddin Hussein said the accusation was a political spin of certain quarters and the answer given also varied and changed with the times.

"I have been consistent from the past in whatever accusation and, rightly, let the accusation have basis and be confirmed by the quarters concerned.

"In political issues, prove it, if it is true we have been bought...no proof, don't talk," he told reporters after opening the Malaysian Defence and Security (MDaS) Hall and Networking here Monday.

He said this when asked by reporters to comment on Mohamad Sabu's accusation on Sunday that the Saudi Arabian foreign minister's confession that his government donated RM2.6 billion to Prime Minister Datuk Seri Najib Razak was visualised as Malaysia and Najib having been 'bought' to join a block headed by that country.

Hishammuddin, who is also Defence Minister, said the matter should not have been blown out of proportion.

"It is better that we look at constructive matters, world security and defence issues which are big challenges to all world leaders," he added.