Ideally you'd have either a scroll of protection from petrification or potion of mirrored eyes. If not, sounds like you should cheat. You can either enable cheats and insta-gib him, or cheat in a potion or scroll and have a warrior take them out.

Also, if you can summon skeletons, they're immune to petrification. Do you have leveled-up cleric? Memorize Animate Dead and then rest. Summon skeletons, haste them, they'll chew up your basilisks.

Or try loading one character with all the buffs you have to improve saving throws? Probably no good, though.

EDIT: You could try throwing some AoE spells at them while they're just off-screen. Cheese strategy. Fireball/Cloudkill.

Throw a couple webs at them while they're just off-screen, then you might be able to arrow them to death? I don't know the range of petrification gaze, might not be good.

EDIT: If you have a mage that has polymorph self, poly into a mustard jelly, is immune to petrifiication. Have jelly move forward and, ideally, use wands or explosive flasks to kill basilisks. Jelly form makes mage immune to all those magical AoE effects.

luckily in my absolutely packed backpacks i found a potion that protects from it, so used it on Minsc and he took care of em, thanks anyway

Good for you having resolved the issue :)

What I usually do here is to send Dynaheir and position her just ouf of the eyesight of the basilisk. Then have throw some lightning bolts around, then have the others pummel the basilisks with ranged weapons, bows sling-shots etc. Oh, and wands of monster summoning works great too.

Kill it!

I know it's now several years late, but if anyone else needs help with this I was able to get past them without protection by giving my party members the permanent-haste boots and having one of them sprint past the basilisks. Then, I had Imoen hide in shadows and transfer the boots to the next party member. I was able to sneak them all past that way, then just walked to the exit.

Those particular basilisks are stuck in that center chamber, being too large to navigate the corridors. I just cast Death Cloud and wait for them to die.

thanks i'll try that

Have your main spellcaster memorize Fireball or load him/her up with Wands Of Fire. Move him just north of the basilisk chamber so that he is out of sight of the basilisks. Basically as far north as he/she can be and still cast into the room. Cast your area effect spells into the center of the room. You won't be able to see the damage, but your bar will let you know when they are toast.

One other thing I want to suggest, since there are a limited number of Potions of Mirror Eyes in the game. You only need ONE potion for the entire party for each area with basilisks. Basilisks will always target the character closest to them, so you give your tank fighter (i.e. Minsk) the potion and everyone else uses ranged weapons. They have very weak physical hits. I was able to easily wipe out this group this way. There is also that wilderness area with them. I did need 2 potions (or scrolls of protection from petrification) there only because it wore off before I finished them all.

This worked like a champ. Fireball and about 5 wand casts and I had crispy critters!