Datuk Seri Mohd Radzi Sheikh Ahmad resigned as Barisan Nasional and Umno secretary-general on Wednesday, saying that his exclusion from the new Cabinet was a factor that would render him ineffective in the two posts.
Speaking to reporters at a press conference at the Putra World Trade Center, Radzi said he would not be able to perform effectively for a number of reasons.
"One of the reasons is because I was dropped from the Cabinet line-up, but there are various other reasons as well," he said, without going into specifics.
When asked if his exclusion from the Cabinet was an indication that he was no longer needed, Radzi said: "You could look at it that way if you want to."
He added that he was not pressured into resigning but admitted that pressure was part of a politician's life.
Radzi said his resignation should not be seen as a split within Umno or the work of certain factions, and he hoped that party members would accept his decision with an open heart and not speculate on it.
"This is a normal process. It is a process of rejuvenation for the party. Someone new will come in who will strengthen the party.
"I am not disappointed. In politics, you cannot be that way. Life goes on," he said.
Radzi said he called Prime Minister Datuk Seri Abdullah Ahmad Badawi Wednesday morning to convey his decision, which Abdullah accepted. He said he has also sent his resignation letter to Abdullah.
"He (Abdullah) did say however that he would continue to listen to my advice in the future. It has been a wonderful four years and I thank the leaders for placing their trust in me."
Radzi said he would continue to support the party as an MP and help the younger MPs to be effective wakil rakyat.
"One of the major complaints that I took note of during the recent campaigning period was that the people viewed our representatives as arrogant.
"The people said the representatives had never come to meet them although they had asked them to come a number of times. I feel this issue must be addressed."
The former Home Affairs Minister was dropped from the new Cabinet line-up announced by Abdullah on Tuesday.
He first contested in the 1982 general election when he won the Kangar parliamentary seat, and retained the seat in the 1986 general election, but had a fallout with Umno in 1987.
The former Perlis state footballer practised law during his brief retirement from politics, and later joined the now defunct Semangat 46 before rejoining Umno in 1990.
He was not picked to contest again until the 2004 general election, where he marked his comeback into active politics by regaining the Kangar seat, which he retained in the recent polls with a 13,671-vote majority.
Datuk Seri Shahidan Kassim, who was the Prime Minister's choice for Perlis Mentri Besar, named Radzi as one of two senior Umno members whom he accused as being responsible for him not being picked for the post.
Bintong assemblyman Datuk Dr Md Isa Sabu was sworn in as Mentri Besar earlier this week.