What should be the marketing budget for an upcoming FMCG brand in Pakistan with heavy competition. Will it be 7% of total sales or ?

Since you are indicating the market has heavy competition and the brand you are bringing is new ... then  I would suggest the percentage you mentioned is very low !! 

To be exact in my assessment ,I need to know how much is this7% of your total sales/revenues ... the specifics of the new brand ... and the nature of the compeition you are facing !!